Re: [RC] [RC] Equipedic and Research on Phase Change Material Temperpedic - Ed & Wendy Hauser
Perception of warmth by a person has much more to
do with heat capacity(how much heat {calories, or BTUs required to warm the
material one degree), and breathability than insulation ability.
A standard old fashioned mattress with a thick
layer of cotton batting is quite a good insulator. It also has a
relatively low heat capacity, and a good ability to let water transpire into the
through it.(this is the so called "wicking" the sellers of clothing like to talk
about)
If you put a plastic mattress cover on it, you will
feel hot and damp because the moisture can't get through it. I have never
been more miserable than the year, on allergists orders, my first wife insisted
on using one.
Tempurpedic material is quite dense, and has a
relatively high heat capacity. The result is that it feels cool when you
get in bed. It is relatively open so moisture transpires and you don't
feel damp.
One of the interesting things about it, is the
glass transition (Tg) temperature is somewhere between 80 and 100 F. This
helps with the slow rebound, that makes it different than usual foam. Of
course, it feels hard when you first lie down (it is below Tg and thus stiff)
but molds to your body as it warms up and goes over the Tg. The maker warns you
not to put a standard insulating mattress pad on it because this would prevent
it from warming and thus conforming to your body.
I purchased one last year. Aside from the
price Wendy and I have never slept better. I still prefer the water bed I
had before we wed, but that is another story.
By the way, a "glass transition" is a type of phase
change. It is different than the usual melting as it happens
over a wide range of temperatures, and the stuff doesn't melt, it just slowly
gets less stiff. Neat science, quite common, but not often covered in
general science courses.
Ed
Ed & Wendy Hauser 2994 Mittower
Road Victor, MT 59875
